Members with 4 wheel disc systems: Can you lock your wheels?

Many OE 4-wheel disc setups have larger dia. discs in the rear, if the piston dia. & proportioning are correct, they work perfectly. Usually they are thinner, and many have to accommodate an internal parking brake drum setup, so the diameter is needed.
The rotors on my Ram 1500 are this way....same diameter but thicker on the front with larger calipers on the front too.